Apparatus and method for ligament fixation

ABSTRACT

A jamming retainer for fixing a ligament in a bone tunnel without excessive sideways pressure on the ligament that may result in tissue necrosis, the jamming retainer including a substantially rigid body with a bore or loop for receiving a ligament or tendon and a bore or ring for receiving a suture for towing the jamming retainer and ligament or tendon through a bone tunnel. Once positioned, the jamming retainer is fixed in the bone tunnel with an interference screw.

REFERENCE TO EARLIER APPLICATIONS

[0001] This application claims the benefit of:

[0002] 1. U.S. Provisional Patent Application Serial No. 60/086,329,filed May 21, 1998 by Kwan-Ho Chan for APPARATUS AND METHOD FOR LIGAMENTFIXATION; and

[0003] 2. U.S. Provisional Patent Application Serial No. 60/125,745,filed Mar. 23, 1999 by Kwan-Ho Chan for APPARATUS AND METHOD FORLIGAMENT FIXATION.

FIELD OF THE INVENTION

[0004] The present invention relates to surgical apparatus and methodsin general, and more particularly to apparatus and methods for fixing aligament in a bone tunnel.

BACKGROUND OF THE INVENTION

[0005] The use of interference screws to fix the ends of abone-tendon-bone complex to the walls of bone tunnels is well known inthe art. It is generally accepted that an interference screw providessufficient fixation of a bone block in a bone tunnel to allow for earlyrehabilitation after ligament surgery, such as in anterior cruciateligament (ACL) reconstruction surgery.

[0006] Some techniques avoid using a bone block to fix a ligament in abone tunnel. Referring to FIG. 1, one such technique involves suspendinga ligament L in a bone tunnel C with a pull-through suture S. Over time,the ligament L and surrounding bone grow together, fixing the ligament Lin place.

[0007] Note: As used herein, the term “ligament L” is meant to refer tothe replacement ligament being fixed in a bone tunnel. To that end, thereplacement ligament L might comprise:

[0008] 1. ligament or tendon or other tissue harvested from thepatient's own tissue (known as autograft tissue); or

[0009] 2. ligament or tendon or other tissue harvested from anotherhuman donor (known as allograft tissue); or

[0010] 3. ligament or tendon or other tissue harvested from an animalsource (know as xenograft tissue); or

[0011] 4. ligament or tendon or other tissue made by tissue engineering;or

[0012] 5. prosthetic ligament made of artificial material; or

[0013] 6. a combination of the above.

[0014] Referring to FIG. 2, another technique uses an interference screwto directly fix ligaments without a bone block (such as a semitendonosisand gracilis tendons) to the walls of the bone tunnel. In this case, theligament L may be towed into place with suture S, which normally isremoved after interference screw fixation has been achieved. However,one disadvantage of direct fixation of the ligament in a bone tunnelwith an interference screw is the risk of slippage of the ligament underload prior to the ligament healing to the bone. Such slippage may occurduring the rehabilitative period when the ligament is subjected torepetitive loading. To provide for a sufficient interference fit, alarge interference screw may be required. However, these largeinterference screws may cause necrosis of the tendon because ofexcessive compression of the ligament against the bony tunnel wall.

OBJECTS OF THE INVENTION

[0015] One object of the present invention is to provide an improvedapparatus and method to augment the interference screw fixation of aligament in a bone tunnel.

[0016] Another object of the present invention is to provide an improvedapparatus and method to resist slippage of the ligament in a bone tunnelunder cyclic loading.

[0017] Yet another object of the present invention is to provide animproved apparatus and method for fixing a ligament in a bone tunnelwithout excessive sideways pressure on the ligament that may result intissue necrosis.

SUMMARY OF THE INVENTION

[0018] The present invention provides a jamming retainer to augment theinterference screw fixation of a ligament in a bone tunnel, wherebyresistance to slippage of the ligament under static and cyclic loadingis improved. The invention also provides a jamming retainer for fixing aligament in a bone tunnel without excessive sideways pressure on theligament that may result in tissue necrosis. The jamming retainerincludes a substantially rigid body with a bore or loop for attaching aligament or tendon to the jamming retainer. The jamming retainer has abore or ring for receiving a suture for towing the jamming retainer andligament or tendon through a bone tunnel. Once the jamming retainer andligament have been positioned within the bone tunnel, e.g., by towing,the ligament is fixed by insertion of an interference screw to compressthe ligament sideways against the wall of the bone canal. However, asnoted above, fixation achieved solely by engagement of the interferencescrew against the ligament is sometimes inadequate; however, with thepresent invention, this fixation is significantly improved through theuse of the jamming retainer in one of two ways. In the first mode,sometimes hereinafter referred to as the “blocking mode”, theinterference screw is advanced into the bone tunnel so as to be justtouching, or just short of touching, the jamming retainer. Anysubsequent proximal slippage of the ligament will draw the jammingretainer against the distal tip of the interference screw. Furtherslippage of the ligament is then prohibited by the jamming retainerabutting against the interference screw. In the second mode, sometimeshereinafter referred to as the “sideways compression mode”, theinterference screw is advanced until the interference screw engages thejamming retainer and pushes the jamming retainer sideways, thus causingthe jamming retainer to be partially embedded in the wall of the bonetunnel. Thus, the jamming retainer is fixed in position by itsengagement with the interference screw and the wall of the bony tunnel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a schematic representation of a tendon drawn into a bonetunnel with a pull-through suture;

[0020]FIG. 2 is a schematic representation of direct fixation of aligament in a bone tunnel using an interference screw;

[0021]FIGS. 3 and 4 are front elevational, and vertical cross-sectionaldetail views, respectively, of an embodiment of a jamming retainer;

[0022]FIGS. 5 and 6 are schematic representations of a tendon beingattached, and snugged, respectively, to the jamming retainer of FIGS. 3and 4;

[0023]FIGS. 7 and 8 are schematic representations of a tendon, attachedto the jamming retainer of FIGS. 3 and 4, drawn into a bone tunnel witha pull-through suture, and secured in the bone tunnel with aninterference screw, respectively;

[0024]FIGS. 9 and 10 are front elevational, and vertical cross-sectionaldetail views, respectively, of another embodiment of a jamming retainer;

[0025]FIGS. 11 and 12 are schematic representations of a tendon beingattached, and snugged, respectively, to the jamming retainer of FIGS. 9and 10;

[0026]FIGS. 13 and 14 are front elevational, and verticalcross-sectional detail views, respectively, of an additional embodimentof a jamming retainer;

[0027]FIGS. 15 and 16 are schematic representations of a tendon beingattached, and snugged, respectively, to the jamming retainer of FIGS. 13and 14;

[0028]FIGS. 17 and 18 are schematic representations of a tendon,attached to the jamming retainer of FIGS. 13 and 14, drawn into a bonetunnel with a pull-through suture, and secured in the bone tunnel withan interference screw, respectively;

[0029]FIG. 19 is a schematic representation of an alternate embodimentfor a spherical jamming retainer;

[0030]FIG. 20 is a schematic representation of an alternate embodimentfor a spherical jamming retainer enhancing fixation of a ligament usingan interference screw;

[0031]FIG. 21 is a front view of an alternate embodiment for a jammingretainer with an incorporated retaining loop;

[0032]FIG. 22 is a side view of an alternate embodiment for a jammingretainer with an incorporated retaining loop;

[0033]FIG. 23 is a schematic side view of a spherical jamming retainerwith a loop for a pull-through suture, and a retaining loop,incorporated therewith;

[0034]FIG. 24 is a front view of an alternate embodiment for a jammingretainer with an incorporated retaining loop;

[0035]FIG. 25 is a side view of an alternate embodiment for a jammingretainer with an incorporated retaining loop;

[0036]FIG. 26 is a schematic side view showing a spherical jammingretainer with transverse bores for passage of sutures;

[0037]FIG. 27 is a partial sectional view of fixation apparatus formedin accordance with the present invention;

[0038]FIG. 28 is a sectional view of a suture retainer portion of thefixation apparatus shown in FIG. 28;

[0039]FIG. 29 is a schematic representation of a tendon attached to afixation device and drawn into a bone tunnel with a pull-through suture;

[0040]FIG. 30 is a schematic representation of the present inventionenhancing fixation of a ligament using an interference screw;

[0041]FIG. 31 is a side elevational view of a ligament inserter; and

[0042]FIG. 32 is a schematic representation of a ligament inserterinserting a ligament attached to a jamming retainer into a bone tunnel.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] The present invention works in conjunction with a standardinterference screw such as a Bioscrew (made by Linvatec) or an RCI screw(made by Smith and Nephew). The invention provides a jamming retainerwhich is attached to a ligament. The jamming retainer is positioned in abone tunnel, and then, preferably, secured relative to the walls of thebone tunnel with an interference screw. More particularly, in onepreferred embodiment, the interference screw urges the jamming retainerlaterally against, and into, the wall of the bone tunnel. Interferencebetween the jamming retainer and the walls of the bone tunnel fixes theligament in the bone tunnel without ligament necrosis.

[0044] The interference screw also bears some of the load imparted onthe jamming retainer by the ligament during normal use of the joint.Thus, even if the interference screw does not create a direct fixationbetween the jamming retainer and the wall of the bone tunnel, anyslippage of the ligament will cause the jamming retainer to abut againstthe interference screw and thus any further slippage is prohibited.Thus, by closely positioning the jamming retainer and interference screwin the bone tunnel slippage of the ligament can be substantiallyprohibited. The jamming retainer may bear some or all of the load of theligament, depending on the degree of direct fixation of the ligamentimparted by the interference screw (and depending on the degree of theload carried by the suture).

[0045] Referring to FIGS. 3 and 4, one embodiment of a jamming retainer100 is a substantially rigid spherical body with longitudinal bores 105for receiving suture. As shown in FIGS. 5 and 6, suture S passes throughone longitudinal bore 105, encircles a ligament L, and passes throughthe other longitudinal bore 105. Once the ligament is snugged againstthe jamming retainer 100, as shown in FIG. 6, the suture is secured witha knot 110.

[0046] Referring to FIGS. 7 and 8, once the ligament L and jammingretainer 100 are secured, the ends of the suture S may be used to towthe jamming retainer 100 and ligament L into position in a bone tunnelC. Once positioned, as shown in FIG. 8, an interference screw I traps,secures or fixes the position of the jamming retainer 100 (and thus theligament L) in the bone tunnel C. In the event that the interferencescrew I is inserted just short of contact with the jamming retainer 100,the ligament L may slip slightly with load applied to it. The ligamentslippage will cause the jamming retainer 100 to migrate towards theinterference screw I. Further migration of the ligament L and thejamming retainer 100 is prevented when the jamming retainer 100 abutsagainst the interference screw I.

[0047] The interference screw I encroaches the wall of the bone tunnelC, thus fixing the position of the interference screw I relative to thebone tunnel C. Preferably, the interference screw I is insertedsufficiently far into bone tunnel C to urge the jamming retainer 100laterally so as to encroach the wall of the bone tunnel C, thus securelyfixing the position of the jamming retainer 100 (and hence the ligamentL) relative to the bone tunnel C.

[0048] Referring to FIGS. 9 and 10, another embodiment of a jammingretainer 200 is a substantially rigid spherical body with longitudinalbores 205 for receiving suture. As shown in FIGS. 11 and 12, suture Spasses through one longitudinal bore 205, encircles a ligament L, andpasses through the other longitudinal bore 205. The jamming retainer 200has a recess 215, which complements the shape of a folded ligament, asshown in FIG. 12. Once the ligament is snugged against the jammingretainer 200, the suture is secured with a knot 210.

[0049] Similar to the jamming retainer 100 as shown in FIGS. 7 and 8,once the ligament L and jamming retainer 200 are secured, the ends ofthe suture S may be used to tow the jamming retainer 200 and ligament Linto position in a bone tunnel C. Once positioned, an interference screwI traps, secures or fixes the position of the jamming retainer 200 (andthus the ligament L) in the bone tunnel C.

[0050] Referring to FIGS. 13 and 14, a further embodiment of theinvention is a threaded-body jamming retainer 300 of substantialrigidity with longitudinal bores 305 for receiving sutures. As shown inFIGS. 15 and 16, suture S passes through one longitudinal bore 305,encircles a ligament L, and passes through the other longitudinal bore305. Once the ligament is snugged against the jamming retainer 300, asshown in FIG. 16, the suture is secured with a knot 310.

[0051] Referring to FIGS. 17 and 18, once the ligament L and jammingretainer 300 are secured, the ends of the suture S may be used to towthe jamming retainer 300 and ligament L into position in a bone tunnelC. Once positioned, an interference screw I traps, secures or fixes theposition of the jamming retainer 300 (and thus the ligament L) in thebone tunnel C. In one preferred embodiment of the invention, thegeometry of the threads of jamming retainer 300 corresponds to thegeometry of the threads of interference screw I, whereby jammingretainer 300 and interference screw I can be intermeshed with oneanother (e.g., in the manner shown in FIG. 18) if so desired.

[0052] One modification of the present invention is the provision of oneor more transverse holes or loops in the jamming retainer, through whichthe ligament and/or sutures can be threaded. In this case, retainingsutures and the suture retainer (see FIGS. 27-30) would not be required.

[0053] Such an alternative embodiment is shown in FIG. 19, where thejamming retainer 400 is in the form of a sphere, and where a bore 405 inthe upper part of the sphere is provided for engagement of thepull-through suture S. The ligament L is passed through a bore 410 (or aloop, described below) that is incorporated as part of the retainer 400.

[0054] When the interference screw I is advanced, as shown in FIG. 20,it will push the spherical retainer 400 sideways and cause it to bepartially embedded in the soft cancellous bone of the bone tunnel C.Alternatively, advancement of interference screw I may be stopped shortof causing lateral movement of spherical retainer 400, in which caseinterference screw I will simply trap the spherical retainer in the bonetunnel.

[0055] Referring to FIGS. 21 and 22, an additional embodiment of thepresent invention provides a threaded-body jamming retainer 500 ofsubstantial rigidity, where a bore 505 in the upper part of the jammingretainer 500 is provided for engagement of a pull-through suture (notshown). A ligament (also not shown) is passed through a bore 510incorporated as part of the retainer 500.

[0056] Referring to FIG. 23, another embodiment of the inventionincludes a spherical jamming retainer 600, where a ring 605 in the upperpart of the jamming retainer 600 is provided for engagement of apull-through suture S. A ligament L is passed through a loop 610incorporated as part of the retainer 600.

[0057] Referring to FIGS. 24 and 25, an additional embodiment of theinvention provides a threaded-body jamming retainer 700 of substantialrigidity, where a bore 705 in the upper part of the jamming retainer 700is provided for engagement of a pull-through suture (not shown). Aligament (also not shown) is passed through a loop 710 incorporated aspart of the retainer 700.

[0058] The ligaments may be tied to yet another embodiment of a jammingretainer 800, shown in FIG. 26. A suture S_(T) is used for towing thejamming retainer 800 through a bone tunnel. A suture S_(L) is used forretaining a ligament L to the jamming retainer 800.

[0059] In another form of the invention, a jamming retainer 900 includestwo parts: a substantially rigid threaded body 905 and a suture retainerpart 910, both shown in FIG. 27. The threaded body 905 is taperedexternally on one end 915. The external threads have the same pitch as amating interference screw I (shown in FIG. 30). The threaded body 905has a partially tapered bore 920 complementary to the tapered body 925of the suture retainer part 910 (FIG. 28). The partially tapered bore iswidest at the end 930 opposite to the externally tapered end 915. Thesuture retainer part 910 has a tapered body 925 to fit inside thepartially tapered bore 920 of the threaded body 905. A ring part 935(FIGS. 27 and 28) is for retaining suture S_(L) tied to the ligament L.One or two #2 sutures maybe used. The ring part 935 is also for passageof the pull-through suture S_(T).

[0060] It should be noted that the complementary taper of the bore 920of the threaded body 905, and the tapered body 925 of the sutureretainer 910, helps to protect the knot 940 of the retaining sutureS_(L). Tension in the suture S_(L) distal to the tip of tapered body 905will tend to draw the suture retainer 910 farther into the tapered bore920. This will cause increased binding of the portion of the sutureS_(L) as it is squeezed between the wall of the tapered body 910 and thewall of the tapered bore 920, thus resisting slippage of the sutureS_(L) and protecting the knot 940.

[0061] Referring also to FIGS. 29 and 30, as the interference screw I isadvanced from below, it first engages the ligament L, compressing itagainst the wall of the bone tunnel C. The interference screw I alsoengages the wall of the bone tunnel C, both by threading mechanics andalso by compression of the cancellous bone of the bone tunnel C. As theinterference screw I is advanced farther, it engages the threaded bodyof the jamming retainer 900. As the combined width of the interferencescrew and the jamming retainer is much larger than the diameter of thebone tunnel C, the advancing interference screw I pushes the jammingretainer 900 sideways. As the jamming retainer 900 is urged sideways,the threads in the threaded body 905 become embedded in the cancellousbone of the bone tunnel C. The engagement of the jamming retainer withthe wall of the bone tunnel C, and with the threads of the interferencescrew I, enhances the fixation of the ligament L via the retainingsutures S_(T) and S_(L).

[0062] The two disadvantages of the two-piece jamming retainer 900 are:

[0063] 1. valuable surgery time is taken up in tying the retainingsutures; and

[0064] 2. the knots may loosen.

[0065] Thus, it is advantageous during manufacture to provide a meansfor engaging the ligament. This can be in the form of a transverse bore,as shown in FIG. 19, or in the form of a bore or loop incorporated aspart of the jamming retainers, as shown in FIGS. 21-25. The bore can bean integral part of the jamming retainer, as shown in FIGS. 21 and 22. Aflexible loop made of suture material such as Dacron or other suturematerial can be incorporated into the retainer during manufacture of theretainer of FIGS. 23-25.

[0066] The jamming retainer can be made of metal, plastic orbioabsorbable materials.

[0067] Although the threaded cylindrical shape, and the non-threadedspherical shape, of the jamming retainer are illustrated here, jammingretainers of other shapes are also possible.

[0068] Although the various embodiments of jamming retainer have beenshown to have different shapes, it is to be appreciated that all theembodiments disclosed will function both in the blocking mode and in thesideways compression mode so as to enhance fixation of the ligament L inthe bone tunnel.

[0069] Referring to FIGS. 31 and 32, rather than towing a jammingretainer and ligament into position, which necessitates additionalincisions and increased drilling, the jamming retainer and ligament maybe pushed into position with a ligament inserter LI. The ligamentinserter LI comprises a handle H, a slender shaft T and means forengaging the jamming retainer or the distal portion of the ligament. Theligament inserter LI uses prongs P₁ and P₂ for maintaining the jammingretainer or ligament during insertion of the jamming retainer andligament in a bone tunnel. As shown in FIG. 32, the ligament L, havingbeen attached to a jamming retainer J, is urged with the jammingretainer through a bone tunnel C. The jamming retainer may then besecured in the bone tunnel using an interference screw in the mannerpreviously discussed.

What is claimed is:
 1. An apparatus for fixing a ligament or tendon in abone tunnel comprising a jamming retainer adapted to retain the ligamentor tendon, said jamming retainer being substantially rigid.
 2. Theapparatus of claim 1, wherein said jamming retainer is fixable in a bonetunnel with an interference screw.
 3. The apparatus of claim 1, saidjamming retainer having one or more of a longitudinal bore, a transversebore or a ring for receiving a suture.
 4. The apparatus of claim 1, saidjamming retainer including a loop for receiving a ligament or tendon. 5.The apparatus of claim 4, wherein said loop is pliable.
 6. The apparatusof claim 1, said jamming retainer having a transverse bore for receivinga ligament or tendon.
 7. The apparatus of claim 1, wherein said jammingretainer has a spherical shape.
 8. The apparatus of claim 1, saidjamming retainer having a recess adapted to complement a shape of theligament or tendon.
 9. The apparatus of claim 1, said jamming retainerhaving exterior threads.
 10. The apparatus of claim 9, wherein saidthreads correspond to threads of an interference screw adapted to fixsaid jamming retainer in the bone tunnel.
 11. The apparatus of claim 1,said jamming retainer defining an external taper.
 12. The apparatus ofclaim 1, said jamming retainer having a bore configured to receive asuture retainer.
 13. The apparatus of claim 12, said suture retainerhaving a shape complementary to said bore.
 14. The apparatus of claim13, said shape being tapered.
 15. The apparatus of claim 12, said sutureretainer and said bore being configured to bind suture receivedtherebetween.
 16. The apparatus of claim 15, said body having a secondbore adapted to permit passage of suture from said bore.
 17. Theapparatus of claim 12, wherein: the suture received between said sutureretainer and said bore retains the ligament or tendon; and said body isfixed in the bone tunnel; whereby tension on the ligament or tendonurges said suture retainer into said bore.
 18. A method for fixing aligament or a tendon in a bone tunnel comprising: retaining the ligamentor tendon with a jamming retainer; and securing the jamming retainer inthe bone tunnel whereby substantial proximal migration of the jammingretainer is prohibited.
 19. The method of claim 18, further comprisingpulling the jamming retainer through the bone tunnel with a suture. 20.The method of claim 18, further comprising pushing the jamming retainerthrough the bone tunnel with a ligament inserter.
 21. The method ofclaim 18, including: connecting the ligament or tendon to the jammingretainer with a suture; and knotting the suture.
 22. The method of claim18, further comprising pulling the jamming retainer through the bonetunnel with one or more free ends of the suture.
 23. The method of claim18, including introducing the ligament or tendon into a loop ortransverse bore in the jamming retainer.
 24. The method of claim 18,including introducing an interference screw into the bone tunnel, theinterference screw being configured to prohibit passage of the jammingretainer from the bone tunnel.
 25. The method of claim 25, wherein theinterference screw encroaches the wall of the bone tunnel.
 26. Themethod of claim 25, said interference screw engaging the jammingretainer.
 27. The method of claim 25, said interference screwthreadingly engaging the jamming retainer.
 28. The method of claim 25,said interference screw urging the jamming retainer into the wall of thebone tunnel.